I found an article today on Hackaday about building a chiller to keep a fishtank's temp down. An aquarium chiller was too expensive so the builder used pc water cooling system instead. The tank needs to be kept below 75 degrees. This chiller reportedly keeps a 6 gallon fish tank at 65 degrees.

Here's the little guy that needs to keep his cool. It's a highly endangered, made in America, Axolotl. They glow in the dark, regenerate body parts, can grow lungs, and then walk away. Normally, they sell for hundreds of dollars. However, if you call now...

The articles don't have a parts list or build instructions. I just like the idea and wanted to share. Maybe someone here will run with the idea.

The use of a peltier "cooler" seems like a wonderful idea in keeping a set temperature stable. It will cool on one side of the plate and heat on the other. This is all based on the direction of current flow. Reversing the current flow switches which side is cooled or heated.

If you are running a circulating pump on one side you could cool when needed then reverse current to heat when that's appropriate.

I've contemplated using a system with a peltier to chill fermentation, but it would work differently, since I really wouldn't want my wort/beer to be recirculated.

The cold water would flow from the peltier/fan device through a SS coil down into the beer, and back up again. Copper would be a big no-no since the acidity of the beer would eat away at the copper and you don't want to drink it. A little copper is ok before fermentation since they yeast eat it, and at that point the pH is higher.

Anyway, after costing out the parts needed, and the effort to build, it just didn't seem to be worth the hassle when a small craigslist fridge and a hacked thermostat would probably work better, and be cheaper to boot.

However, I do have plans to build a 2-section cooler chiller with an arduino controller. Kind of like a Swamp Cooler, but with ice water from another cooler pumped in as needed to chill it. When the ice block from one side is gone, simply replace with another from the freezer. My gut estimate is that you might only need to replace it one time during the initial fermentation, depending on the size of the ice block and the ambient temp and the thermal properties of the coolers.

When the temp rises, the controller turns on a pump, which pumps water from Ice Block side into the cooler with the fermenter. A hole in the side returns water to the ice block cooler.

I guess what I was thinking of was to recirculate water through a chiller as you described and use the small peltier to siphon off the heat. This shouldn't be too hard and the current draw shouldn't be too great.

I'm still new to brewing so the acidity on the copper problem was news to me but thank you for dropping that knowledge.

Since you're talking about using a block of ice to do this you're basically using a compressor system to create the ice before hand. What I had in mind was a fully enclosed insulated system that would allow the peltier to draw heat from the recirculating water and exhaust it off the hot side for cooling affect. It's really uncomplicated if you just have a fan <- heatsink <- peltier <- heatsink <-circulating water. The only change is the peltier pulling heat instead of ice.

It seems others have tried some of this as I've searched the forums. There may be some roadblocks that I'm not foreseeing.

I'm from a computer background so this really piqued my interest. Some peple use similar systems to cool processors. Some hardware is already off the shelf to get this going.

Another thought would be to circulate the water through a radiator with a fan to dissapate the heat. Given the need to cool it's just a matter of removing the heat and I like the idea of keeping it simple without cutting into a fridge or something similar.

I actually have access to a couple of free, large peltiers and I still don't want to build this. Part of it is due to me already having several projects, and the other fact that I already have 3 fermentation chambers.

If I really needed to build something very small, like if I lived in an apartment, then I'd probably start work on it.

The fact is, it doesn't take much energy to counteract what heat the yeast put out. I'm sure a peltier could do it easily with more or less direct contact with the wort. (If the fermenter were to be kept in an area close to room temperature.)

The peltier portion would be easy to deal with. The difficulty is only in building a food-safe, fermenter-friendly, efficient transfer system. The design I thought up hung off the neck of a carboy, with the cooling coils sticking up through the bung and connected to the peltier with short silicone hose. The coil and heatsink block would be filled up just prior to the hose connecting to the coil, to create prime and prevent cavitation.

Really the whole thing could fit in a space practically no bigger than the fermenter. Any form of insulation would help it, such as a blanket, or what have you.

But, by the time you price a peltier, a non-copper heatsink, and Stainless tubing for coils, then add the effort involved in bending the tubing other assembling, it's more complicated than at first glance.

You also have to have a thermometer or thermocouple to monitor or control the temp.

As far as the radiator and fan, I think that you will only get as cool as the ambient air, right? Plus you need a pump again. So the only thing missing is the peltier, which is not the hard part.

AS a note, I must mention that the design in my head is based off a carboy scenario. This could be a bit easier with buckets, since the coil would be easier to work with.

If copper were not toxic in fermented beer, this would be much simpler since copper is a great thermal conductor, and is readily available and not very expensive.